Fluorophosphite containing catalysts for hydroformylation processes

ABSTRACT

Novel fluorophosphite compounds having the structure of general formula (I): 
                         
where Ar 1  and Ar 2  are aryl groups containing 4 to 30 carbon atoms; R1 to R6 are H or alkyl or aryl hydrocarbon radicals containing 1 to 40 carbon atoms; and X is a connecting group or a simple chemical bond, were developed and found to be very active for hydroformylation processes for ethylenically unsaturated substrates. Catalyst solutions prepared from these compounds with a Rh metal show an unusual “ligand acceleration effect” for simple alkenes, i.e., the hydroformylation activity increases as the concentration of ligand increases, and are capable of producing linear or branched aldehydes under typical hydroformylation conditions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 61/016,661 filed on Dec. 26, 2007, the disclosure of which isincorporated herein by reference to the extent it does not contradictthe disclosures herein.

FIELD OF THE INVENTION

This invention generally relates to fluorophosphite compounds, acatalyst solution containing the same, and a hydroformylation processusing the catalyst solution.

BACKGROUND OF THE INVENTION

The hydroformylation reaction, also known as the oxo reaction, is usedextensively in commercial processes for the preparation of aldehydes bythe reaction of one mole of an olefin with one mole each of hydrogen andcarbon monoxide. One use of the reaction is in the preparation ofnormal- and iso-butyraldehyde from propylene. The ratio of the amount ofthe normal aldehyde product to the amount of the iso aldehyde producttypically is referred to as the normal-to-iso (N:I) or thenormal-to-branched (N:B) ratio. In the case of propylene, the normal-and iso-butyraldehydes obtained from propylene are in turn convertedinto many commercially valuable chemical products such as, for example,n-butanol, 2-ethyl-hexanol, n-butyric acid, iso-butanol, neo-pentylglycol, 2,2,4-trimethyl-1,3-pentanediol, and the mono-isobutyrate anddi-isobutyrate esters of 2,2,4-trimethyl-1,3-pentanediol.

In most cases, a phosphorus ligand-containing catalyst is used for theoxo process (so called “low pressure hydroformylation process”).Phosphorus ligands not only can stabilize the metal, but can alsoregulate the catalyst activity and selectivity. Oxo catalyst activityoften decreases as the amount of phosphorus ligands increases while thecatalyst stability increases with increasing amounts of ligand.Therefore, there exists an optimum concentration of phosphorus ligandsfor operating an oxo reactor which is the result of a tradeoff betweenincreased stability and reduced catalyst activity.

In reality, the gradual loss of phosphorus ligands is inevitable becauseof decomposition and other reasons. In some cases, such as overflowreactors, the decomposition of ligands may be worsened due to the hightemperature required to separate catalysts from products. In practice,fresh phosphorus ligands have to be replenished to the reactor on aregular basis to compensate for the loss of ligands.

Thus, there is a need in the art for ligands that not only stabilize thecatalyst at higher concentrations, but can also increase the metalcatalyst activity at such concentrations.

SUMMARY OF THE INVENTION

A class of ligands has been discovered that can substantially increasethe Rh catalyst activity by simply increasing the novel fluorophosphiteligand concentration. In some embodiments, the ligand offers one or morebenefits, such as enhanced catalyst stability, increased productionrate, and reduced daily operation costs due to eliminated needs forreplenishing ligands.

In one aspect, the present invention provides a fluorophosphite compoundhaving the structure of formula (I):

wherein

-   -   Ar₁ and Ar₂ are each independently selected from aryl groups        containing 4 to 30 carbon atoms;    -   R1 to R6 are each independently selected from H and hydrocarbyl        containing 1 to 40 carbon atoms; and    -   X is        -   (i) a chemical bond directly between ring carbon atoms of            each aromatic group, except when R1 to R4 are each methyl,        -   (ii) a heteroatom selected from O, Si, and N, or    -   (iii) a group having the formula

wherein R13 and R14 are each independently selected from hydrogen andalkyl or aryl groups having 1 to 10 carbon atoms.

In a second aspect, the present invention provides a catalyst solutioncomprising:

-   -   (a) a fluorophosphite compound;    -   (b) a Group VIII metal or rhenium; and    -   (c) a hydroformylation solvent,        wherein the fluorophosphite compound has the structure of        formula (I):

wherein

-   -   Ar₁ and Ar₂ are each independently selected from aryl groups        containing 4 to 30 carbon atoms;    -   R1 to R6 are each independently selected from H and hydrocarbyl        containing 1 to 40 carbon atoms; and    -   X is        -   (i) a chemical bond directly between ring carbon atoms of            each aromatic group,        -   (ii) a heteroatom, or        -   (iii) a group having the formula

wherein R13 and R14 are each independently selected from hydrogen andalkyl or aryl having 1 to 10 carbon atoms. In some embodiments, R13 andR14 are each independently selected from hydrogen and alkyl groupshaving one or two carbon atoms. In some embodiments, R13 and R14 areeach independently selected from hydrogen and methyl groups.

In a third aspect, the present invention provides a process forpreparing aldehydes, comprising contacting an olefin with hydrogen andcarbon monoxide, under hydroformylation conditions, in the presence ofthe catalyst solution herein described.

DETAILED DESCRIPTION OF THE INVENTION

New fluorophosphite compounds have been discovered that are useful asligands in hydroformylation reactions. The invention thus provides newfluorophosphite compounds. The invention further provides highly activecatalyst solution for use in hydroformylation reactions.

The catalyst solution comprises:

(a) a fluorophosphite compound;

(b) a Group VIII metal or rhenium; and

(c) a hydroformylation solvent.

The fluorophosphite compound according to the invention has thestructure of formula (I):

wherein

-   -   Ar₁ and Ar₂ are each independently selected from aryl groups        containing 4 to 30 carbon atoms;    -   R1 to R6 are each independently selected from H and hydrocarbyl        containing 1 to 40 carbon atoms; and    -   X is        -   (i) a chemical bond directly between ring carbon atoms of            each aromatic group,        -   (ii) a heteroatom, or        -   (iii) a group having the formula

wherein R13 and R14 are each independently selected from hydrogen andalkyl or aryl having 1 to 10 carbon atoms.

In some embodiments, X is not a chemical bond when R1 to R4 are allmethyl.

The heteroatom can be any atom other than carbon that can form the bondswith the two aryl rings as shown in Formula (I) without compromising theefficacy of the ligand. In some embodiments, the heteroatom is selectedfrom sulfur, oxygen, nitrogen, and silicon, provided that the siliconand nitrogen will have additional substituents bonded thereto tocomplete the atoms bonding capability. Substituents which are acceptableinclude alkyl groups of 1 to 20 carbon atoms and aromatic groups of 6 to20 carbon atoms. In some embodiments, the heteroatom is selected from O,Si, and N, again, with additional atoms bonded to a Si or N.

Examples of the aryl groups that Ar₁ and Ar₂ can represent includecarbocyclic aryl such as phenyl, naphthyl, anthracenyl, and substitutedderivatives thereof. Suitable substituents include alkyl groups of 1 to20 carbon atoms, aromatic groups of 6 to 20 carbon atoms, alkoxy,aryloxy, halogens, carboxylic acids and derivatives thereof such asesters, amides or the carboxylate salt. Additionally suitablesubstituents include sulfonic acids, the salts of sulfonic acids andderivatives thereof such as esters and amides. In particular, Ar₁ andAr₂ can each individually represent radicals having any one of theformulas (II)-(IV):

wherein R7 and R8 may represent one or more substituents independentlyselected from alkyl, alkoxy, halogen, cycloalkoxy, formyl, alkanoyl,cycloalkyl, aryl, aryloxy, aroyl, carboxyl, carboxylate salts,alkoxy-carbonyl, alkanoyloxy, cyano, sulfonic acid, sulfonate salts, andthe like. In some embodiments the alkyl moiety of the aforesaid alkyl,alkoxy, alkanoyl, alkoxycarbonyl and alkanoyloxy groups contains up toabout 8 carbon atoms. Although it is possible for m to represent 0 to 5and for n to represent 0 to 7, in some embodiments, the value of each ofm and n will not exceed 2. In some embodiments, R7 and R8 representlower alkyl groups, i.e., straight-chain and branched-chain alkyl of upto about 10 carbon atoms, and m and n each represent 0, 1, or 2. In someembodiments, R7 and R8 represent lower alkyl groups, i.e.,straight-chain and branched-chain alkyl of up to about 4 carbon atoms,and m and n each represent 0, 1, or 2.

The hydrocarbyl groups represented by R1 to R4 are selected fromunsubstituted and substituted alkyl, cycloalkyl and aryl groupscontaining up to about 40 carbon atoms. In some embodiments, the totalcarbon content of R1 to R4 is in the range of about 1 to 15 carbonatoms. Examples of the alkyl groups that R1 to R4 can represent includemethyl, ethyl, butyl, pentyl, hexyl, 2-ethylhexyl, octyl, decyl,dodecyl, octadecyl, and various isomers thereof. The alkyl groups may besubstituted, for example, with up to two substituents such as alkoxy,cycloalkoxy, formyl, alkanoyl, cycloalkyl, aryl, aryloxy, aroyl,carboxyl, carboxylate salts, alkoxycarbonyl, alkanoyloxy, cyano,sulfonic acid, sulfonate salts, and the like. Cyclopentyl, cyclohexyl,and cycloheptyl are examples of the cycloalkyl groups that R1 to R4 canrepresent. The cycloalkyl groups may be substituted with alkyl or any ofthe substituents described with respect to the possible substitutedalkyl groups. In some embodiments, the alkyl and cycloalkyl groups thatR1 to R4 can represent are alkyl of up to about 8 carbon atoms, benzyl,cyclopentyl, cyclohexyl, or cycloheptyl.

Examples of the aryl groups that R1 to R4 can represent includecarbocyclic aryl such as phenyl, naphthyl, anthracenyl, and substitutedderivatives thereof. Examples of the carbocyclic aryl groups that R1 toR4 can represent include radicals having the formulas (V)-(VII):

wherein R9 and R10 may represent one or more substituents independentlyselected from alkyl, alkoxy, halogen, cycloalkoxy, formyl, alkanoyl,cycloalkyl, aryl, aryloxy, aroyl, carboxyl, carboxylate salts,alkoxy-carbonyl, alkanoyloxy, cyano, sulfonic acid, sulfonate salts, andthe like. In some embodiments the alkyl moiety of the aforesaid alkyl,alkoxy, alkanoyl, alkoxycarbonyl, and alkanoyloxy groups contains up toabout 8 carbon atoms. Although it is possible for p to represent 0 to 5and for q to represent 0 to 7, in some embodiments, the value of each ofp and q will not exceed 2. In some embodiments R9 and R10 representlower alkyl groups, i.e., straight-chain and branched-chain alkyl of upto about 4 carbon atoms, and m and n each represent 0, 1, or 2.

The hydrocarbyl groups represented by R5 and R6 may be the same ordifferent, separate or combined, and are selected from unsubstituted andsubstituted alkyl, cycloalkyl, and aryl groups containing a total of upto about 40 carbon atoms. The total carbon content of substituents of R5to R6 in some embodiments is in the range of about 1 to 35 carbon atoms.Examples of the alkyl groups that R5 and R6 can represent includemethyl, ethyl, butyl, pentyl, hexyl, 2-ethylhexyl, octyl, decyl,dodecyl, octadecyl, 1-alkylbenzyl, and various isomers thereof. Thealkyl groups may be substituted, for example, with up to twosubstituents such as alkoxy, cycloalkoxy, formyl, alkanoyl, cycloalkyl,aryl, aryloxy, aroyl, carboxyl, carboxylate salts, alkoxycarbonyl,alkanoyloxy, cyano, sulfonic acid, sulfonate salts, and the like.Cyclopentyl, cyclohexyl, and cycloheptyl are examples of the cycloalkylgroups that R5 and R6 individually can represent. The cycloalkyl groupsmay be substituted with alkyl or any of the substituents described withrespect to the possible substituted alkyl groups. In some embodimentsthe alkyl and cycloalkyl groups that R5 and R6 represent are alkyl of upto about 10 carbon atoms such as benzyl, 1-alkylbenzyl, cyclopentyl,cyclohexyl, or cycloheptyl, etc.

Examples of the aryl groups that R5 and R6 can represent includecarbocyclic aryl such as phenyl, naphthyl, anthracenyl, and substitutedderivatives thereof. Examples of the carbocyclic aryl groups that R5 andR6 can represent include radicals having the formulas (VIII)-(X):

wherein R11 and R12 may represent one or more substituents independentlyselected from alkyl, alkoxy, halogen, cycloalkoxy, formyl, alkanoyl,cycloalkyl, aryl, aryloxy, aroyl, carboxyl, carboxylate salts,alkoxy-carbonyl, alkanoyloxy, cyano, sulfonic acid, sulfonate salts, andthe like. In some embodiments, the alkyl moiety of the aforesaid alkyl,alkoxy, alkanoyl, alkoxycarbonyl, and alkanoyloxy groups contains up toabout 8 carbon atoms. Although it is possible for r to represent 0 to 5and for s to represent 0 to 7, in some embodiments, the value of each ofr and s will not exceed 2. R11 and R12 represent lower alkyl groups,i.e., straight-chain and branched-chain alkyl of up to about 10 carbonatoms, and r and s each represent 0, 1, or 2.

In some embodiments, R1 to R6 in combination or collectively mayrepresent a divalent hydrocarbyl group containing up to about 40 carbonatoms. In some embodiments, the divalent hydrocarbyl group contains fromabout 12 to 36 carbon atoms. Examples of such divalent groups includealkyl of about 2 to 12 carbon atoms, cyclohexyl, and aryl. Specificexamples of the alkyl and cycloalkyl groups include ethyl, trimethyl,1,3-butanediyl, 2,2-dimethyl-1,3-propanediyl, 1,1,2-triphenylethanediyl,2,2,4-trimethyl-1,3-pentanediyl, 1,2-cyclohexyl, and the like.

In some embodiments, the fluorophosphite compound according to theinvention has the structure of formula (XI):

Wherein R15 is selected from hydrogen and alkyl or aryl having 1 to 10carbon atoms. In some embodiments, the fluorophosphite compound has thefollowing structure:

In some embodiments, the fluorophosphite compound has the followingstructure:

The fluorophosphite compounds of this invention can be prepared by anyeffective method. A variety of methods for preparing fluorophosphatesare reported in the literature. For example, it has been found that thefluorophosphites can be prepared by using a (benzyl)phenol startingmaterial such as 2,2′-methylene bis(4,6-di(α,α-dimethylbenzyl)phenol)and following the procedures described in U.S. Pat. No. 4,912,155;Tullock et al., J. Org. Chem., 25, 2016 (1960); White et al., J. Am.Chem. Soc., 92, 7125 (1970); Meyer et al., Z. Naturforsch, Bi. Chem.Sci., 48, 659 (1993); or Puckette, in “Catalysis of Organic Reactions”,Edited by S. R. Schmidt, CRC Press (2006), pp. 31-38.

The novel catalyst systems provided by the present invention comprise acombination of one or more transition metals selected from the GroupVIII metals and rhenium and one or more of the fluorophosphite compoundsdescribed in detail hereinabove. The transition metal may be provided inthe form of various metal compounds such as carboxylate salts of thetransition metal. In some embodiments, the metal is rhodium.

Rhodium compounds that may be used as a source of rhodium for the activecatalyst include rhodium (II) or rhodium (III) salts of carboxylicacids, examples of which include di-rhodium tetraacetate dihydrate,rhodium (II) acetate, rhodium (II) isobutyrate, rhodium (II)2-ethylhexanoate, rhodium (II) benzoate, and rhodium (II) octanoate.Also, rhodium carbonyl species such as Rh₄(CO)₁₂, Rh₆(CO)₁₆, and rhodium(I) acetylacetonate dicarbonyl may be suitable rhodium feeds.Additionally, rhodium organophosphine complexes such astris(triphenylphosphine)rhodium carbonyl hydride may be used when thephosphine moieties of the complex fed are easily displaced by thephosphite ligands of the present invention. Other rhodium sourcesinclude rhodium salts of strong mineral acids such as chlorides,bromides, nitrates, sulfates, phosphates, and the like.

The ratio of gram moles fluorophosphite ligand to gram atoms transitionmetal can vary over a wide range, e.g., gram mole fluorophosphite:gramatom transition metal ratio of about 1:1 to 400:1. Forrhodium-containing catalyst systems, the gram mole fluorophosphite:gramatom rhodium ratio in some embodiments is in the range of about 1:1 to200:1 with ratios in the range of about 1:1 to 120:1. The absoluteconcentration of rhodium in the reaction mixture or solution may varyfrom 1 mg/liter up to 5000 mg/liter or more. In some embodiments of thisinvention, the normal concentration of rhodium in the reaction solutionis in the range of about 20 to 300 mg/liter. Concentrations of rhodiumlower than this range generally yield lower reaction rates with mostolefin reactants and/or require reactor operating temperatures that areso high as to be detrimental to catalyst stability. Concentrations abovethis range involve higher rhodium costs.

No special or unusual techniques are required for preparing the catalystsystems and solutions of the present invention, although in someembodiments a catalyst of high activity is obtained if all manipulationsof the rhodium and fluorophosphite ligand components are carried outunder an inert atmosphere, e.g., nitrogen, argon, and the like. Thedesired quantities of a suitable rhodium compound and ligand are chargedto the reactor in a suitable solvent. The sequence in which the variouscatalyst components or reactants are charged to the reactor is notcritical.

The hydroformylation solvent may be selected from a wide variety ofcompounds, mixture of compounds, or materials that are liquid at thepressure at which the process is being operated. Such compounds andmaterials include various alkanes, cycloalkanes, alkenes, cycloalkenes,carbocyclic aromatic compounds, alcohols, esters, ketones, acetals,ethers, and water. Specific examples of such solvents include alkane andcycloalkanes such as dodecane, decalin, octane, iso-octane mixtures,cyclohexane, cyclooctane, cyclododecane, methylcyclohexane; aromatichydrocarbons such as benzene, toluene, xylene isomers, tetralin, cumene,alkyl-substituted aromatic compounds such as the isomers ofdiisopropylbenzene, triisopropylbenzene and tert-butylbenzene; alkenesand cycloalkenes such as 1,7-octadiene, dicyclopentadiene,1,5-cyclooctadiene, octene-1, octene-2,4-vinylcyclohexene, cyclohexene,1,5,9-cyclododecatriene, 1-pentene; crude hydrocarbon mixtures such asnaphtha, mineral oils and kerosene; and high-boiling esters such as2,2,4-trimethyl-1,3-pentanediol diisobutyrate. The aldehyde product ofthe hydroformylation process also may be used.

In some embodiments, the solvent is the higher boiling by-products thatare naturally formed during the process of the hydroformylation reactionand the subsequent steps, e.g., distillations, that may be required foraldehyde product isolation. The main criterion for the solvent is thatit dissolves the catalyst and olefin substrate and does not act as apoison to the catalyst. Some examples of solvents for the production ofvolatile aldehydes, e.g., butyraldehydes, are those that aresufficiently high boiling to remain, for the most part, in a gas spargedreactor. Some examples of solvents and solvent combinations that areuseful in the production of less volatile and non-volatile aldehydeproducts include 1-methyl-2-pyrrolidinone, dimethyl-formamide,perfluorinated solvents such as perfluoro-kerosene, sulfolane, water,and high boiling hydrocarbon liquids as well as combinations of thesesolvents. Non-hydroxylic compounds, in general, and hydrocarbons, inparticular, may be used advantageously as the hydroformylation solventsince their use can minimize decomposition of the fluorophosphiteligands.

In another aspect, the present invention provides a process forpreparing aldehydes, comprising contacting an olefin with hydrogen andcarbon monoxide, under hydroformylation conditions, in the presence ofthe catalyst solution herein described.

The reaction conditions for the process of the present invention can beconventional hydroformylation conditions. The process may be carried outat temperatures in the range of about 20° to 200° C., in someembodiments the hydroformylation reaction temperatures are from 50° to135° C. In some embodiments, reaction temperatures range from 75° to125° C. Higher reactor temperatures can increase the rate of catalystdecomposition while lower reactor temperatures can result in relativelyslow reaction rates. The total reaction pressure may range from aboutambient or atmospheric up to 70 bars absolute (about 1000 psig). In someembodiments, pressure ranges from about 8 to 28 bars absolute (about 100to 400 psig).

The hydrogen:carbon monoxide mole ratio in the reactor likewise may varyconsiderably ranging from 10:1 to 1:10, and the sum of the absolutepartial pressures of hydrogen and carbon monoxide may range from 0.3 to36 bars absolute. The partial pressures of the ratio of the hydrogen tocarbon monoxide in the feed can be selected according to thelinear:branched isomer ratio desired. Generally, the partial pressure ofhydrogen and carbon monoxide in the reactor can be maintained within therange of about 1.4 to 13.8 bars absolute (about 20 to 200 psia) for eachgas. The partial pressure of carbon monoxide in the reactor can bemaintained within the range of about 1.4 to 13.8 bars absolute (about 20to 200 psia) and can be varied independently of the hydrogen partialpressure. The molar ratio of hydrogen to carbon monoxide can be variedwidely within these partial pressure ranges for the hydrogen and carbonmonoxide. The ratios of hydrogen-to-carbon monoxide and the partialpressure of each in the synthesis gas (syn gas—carbon monoxide andhydrogen) can be readily changed by the addition of either hydrogen orcarbon monoxide to the syn gas stream. With the fluorophosphite ligandsdescribed herein, the ratio of linear to branched products can be variedwidely by changing the partial pressures of the carbon monoxide in thereactor.

Any of the known hydroformylation reactor designs or configurations suchas overflow reactors and vapor take-off reactors may be used in carryingout the process provided by the present invention. Thus, a gas-sparged,vapor take-off reactor design as disclosed in the examples set forthherein may be used. In this mode of operation, the catalyst which isdissolved in a high boiling organic solvent under pressure does notleave the reaction zone while the aldehyde product is taken overhead bythe unreacted gases. The overhead gases then are chilled in avapor/liquid separator to liquefy the aldehyde product and the gases canbe recycled to the reactor. The liquid product is let down toatmospheric pressure for separation and purification by conventionaltechniques. The process also may be practiced in a batchwise manner bycontacting the olefin, hydrogen and carbon monoxide with the presentcatalyst in an autoclave.

A reactor design where catalyst and feedstock are pumped into a reactorand allowed to overflow with product aldehyde, i.e. liquid overflowreactor design, is also suitable. For example, high boiling aldehydeproducts such as nonyl aldehydes may be prepared in a continuous mannerwith the aldehyde product being removed from the reactor zone as aliquid in combination with the catalyst. The aldehyde product may beseparated from the catalyst by conventional means such as bydistillation or extraction, and the catalyst then recycled back to thereactor. Water soluble aldehyde products, such as hydroxy butyraldehydeproducts obtained by the hydroformylation of allyl alcohol, can beseparated from the catalyst by extraction techniques. A trickle-bedreactor design is also suitable for this process. It will be apparent tothose skilled in the art that other reactor schemes may be used withthis invention.

The olefin used as the starting material for this invention is notparticularly limiting. Specifically, the olefin can be ethylene,propylene, butene, pentene, hexene, octene, styrene, non-conjugateddienes such as 1,5-hexadiene, and blends of these olefins. Furthermore,the olefin may be substituted with functional groups so long as they donot interfere with the hydroformylation reaction. Suitable substituentson the olefin include any functional group that does not interfere withthe hydroformylation reaction and includes groups such as carboxylicacids and derivatives thereof such as esters and amides, alcohols,nitrites, and ethers. Examples of substituted olefins include esterssuch as methyl acrylate or methyl oleate, alcohols such as allyl alcoholand 1-hydroxy-2,7-octadiene, and nitriles such as acrylonitrile.

The amount of olefin present in the reaction mixture can also vary. Forexample, relatively high-boiling olefins such as 1-octene may functionboth as the olefin reactant and the process solvent. In thehydroformylation of a gaseous olefin feedstock such as propylene, thepartial pressures in the vapor space in the reactor are in the range ofabout 0.07 to 35 bars absolute. The rate of reaction can be favored byhigh concentrations of olefin in the reactor. In the hydroformylation ofpropylene, the partial pressure of propylene in some embodiments isgreater than 1.4 bars, e.g., from about 1.4 to 10 bars absolute. In thecase of ethylene hydroformylation, the partial pressure of ethylene inthe reactor in some embodiments is greater than 0.14 bars absolute.

This invention can be further illustrated by the following examples ofembodiments thereof, although it will be understood that these examplesare included merely for purposes of illustration and are not intended tolimit the scope of the invention. Unless otherwise indicated, allpercentages are by weight. As used throughout this application, thereference to a molecule or moiety as being “substituted” means that themolecule or moiety contains one or more substituent in place of where ahydrogen atom would be on the molecule or moiety identified. Thus, a“substituted” aryl molecule having alkyl substituents would include, forexample, an alkylbenzene such as toluene.

EXAMPLES

Preparation of Ligand A

Ligand A was synthesized from starting material 2,2′-methylenebis(4,6-di(α,α-dimethylbenzyl)phenol) by following the proceduresdescribed in U.S. Pat. No. 4,912,155; the entire content of which ishereby incorporated by reference. Ligand A is very soluble in commonorganic solvents such as toluene, acetone, cyclohexane, ethyl acetate,etc.

Spectroscopic Data of Ligand A:

Ligand A is a new compound and shows a doublet on 31P NMR (in CDCl₃)centered at 121.6 ppm (J_(F-P)=1320 Hz). The chemical shift of ¹⁹F NMRof Ligand A shows a doublet centered at −64.9 ppm (J_(P-F)=1301 Hz). Thechemical shift (in ppm) of ¹H NMR of Ligand A in CDCl₃ is as follows:1.42 (s, 6H), 1.58 (s, 6H), 1.67 (s, 12H), 3.28 (d, 1H), 3.90(dd, 1H),6.96-7.31 (m, 24H).

Preparation of Ligand B

Ligand B was synthesized from starting material2,4-di-(α,α-dimethylbenzyl)phenol by following the procedures describedin U.S. Pat. No. 4,912,155. Ligand B is slightly less soluble thanLigand A in common organic solvents.

Spectroscopic Data of Ligand B:

Ligand B is a new compound and shows a doublet on 31P NMR (in CDCl₃)centered at 119.89 ppm (J_(F-P)=1265 Hz). The chemical shift of ¹⁹F NMRof Ligand B shows a doublet centered at −57.81 ppm (J_(P-F)=1255 Hz).The chemical shift (in ppm) of ¹H NMR of Ligand B in CDCl₃ is asfollows: 1.54 (s, 6H), 1.57 (s, 6H), 1.69 (s, 12H), 6.47 (d, 2H), 7.03(d, 2H), 7.13-7.35 (m, 22H).

Ligand C

Ligand C is a compound taken from Puckette, in “Catalysis of OrganicReactions”, Edited by S. R. Schmidt, CRC Press (2006), p. 31. The liganddescribed in this literature is also a fluorophosphite (Ethanox 398™,2,2′-ethylidenebis(4,6-di-tert-butylphenyl)fluorophosphite).

Ligand D

Ligand D was synthesized from starting material2,4-di-(α,α-dimethylbenzyl)phenol by following the procedures describedin U.S. Pat. No. 4,912,155.

Ligand D is a new compound and shows a doublet on 31P NMR (in CDCl₃)centered at 105.9 ppm (J_(F-P)=1286 Hz). The chemical shift of ¹⁹F NMRof Ligand A shows a doublet centered at −61.5 ppm (J_(P-F)=1297 Hz). Thechemical shift (in ppm) of ¹H NMR of Ligand D in CDCl₃ is as follows:1.39 (d, 3H), 1.50 (s, 6H), 1.62 (s, 6H), 1.70(s, 12H), 4.31 (br s, 1H),6.97(s, 2H), 7.11-7.31 (m, 22H).Hydroformylation Process Set-Up

The hydroformylation process in which propylene is allowed to react withhydrogen and carbon monoxide to produce butyraldehydes was carried outin a vapor take-off reactor made up of a vertically arranged stainlesssteel pipe having a 2.5 cm inside diameter and a length of 1.2 meters.The reactor was encased in an external jacket that was connected to ahot oil machine. The reactor has a filter element welded into the sidedown near the bottom of the reactor for the inlet of gaseous reactants.The reactor contained a thermocouple which was arranged axially with thereactor in its center for accurate measurement of the temperature of thehydroformylation reaction mixture. The bottom of the reactor has a highpressure tubing connection that was connected to a cross. One of theconnections to the cross permitted the addition of non-gaseous reactantssuch as higher boiling alkenes or make-up solvents, another led to thehigh-pressure connection of a differential pressure (D/P) cell that wasused to measure catalyst level in the reactor and the bottom connectionwas used for draining the catalyst solution at the end of the run.

In the hydroformylation of propylene in a vapor take-off mode ofoperation, the hydroformylation reaction mixture or solution containingthe catalyst was sparged under pressure with the incoming reactants ofpropylene, hydrogen and carbon monoxide as well as any inert feed suchas nitrogen. As butyraldehyde was formed in the catalyst solution, itand unreacted reactant gases were removed as a vapor from the top of thereactor by a side-port. The vapor removed was chilled in a high-pressureseparator where the butyraldehyde product was condensed along with someof the unreacted propylene. The uncondensed gases were let down toatmospheric pressure via the pressure control valve. These gases passedthrough a series of dry-ice traps where any other aldehyde product wascollected. The product from the high-pressure separator was combinedwith that of the traps, and was subsequently weighed and analyzed bystandard gas/liquid phase chromatography (GC/LC) techniques for the netweight and normal/iso ratio of the butyraldehyde product.

The gaseous feeds to the reactor were fed to the reactor via twincylinder manifolds and high-pressure regulators. The hydrogen passedthrough a mass flow controller and then through a commercially available“Deoxo” (registered trademark of Englehard Inc.) catalyst bed to removeany oxygen contamination. The carbon monoxide passed through an ironcarbonyl removal bed (as disclosed in U.S. Pat. No. 4,608,239), asimilar “Deoxo” bed heated to 125° C., and then a mass flow controller.Nitrogen can be added to the feed mixture as an inert gas. Nitrogen,when added, was metered in and then mixed with the hydrogen feed priorto the hydrogen Deoxo bed. Propylene was fed to the reactor from feedtanks that were pressurized with hydrogen and was controlled using aliquid mass flow meter. All gases and propylene were passed through apreheater to ensure complete vaporization of the liquid propylene priorto entering the reactor.

Comparative Examples 1-3 Ligand C

Comparative Examples 1-3 were taken directly from Puckette, “Catalysisof Organic Reactions”, Edited by S. R. Schmidt, CRC Press (2006), pp.31-38, to illustrate that hydroformylation activity decreases as themolar ratio of ligand to Rh increases (the concentration of ligandincreases). The ligand described in this literature is a fluorophosphite(Ethanox 398™,2,2′-ethylidenebis(4,6-di-tert-butylphenyl)fluorophosphite) (Ligand C).

According to the literature, the reactions were conducted at 260 psig,115° C., 1:1 H2/CO, 54 psia C₃H₆, and 190 mL ofbis-2-ethylhexylphthalate solvent (DOP) with different amounts ofligand. The data is presented in Table 1 below and catalyst activity isexpressed as kilograms of butyaldehyde per gram Rh per hour.

Comparative Example 4 Ligand B

This example illustrates a typical hydroformylation run and the use ofLigand “B” for hydroformylation of propylene.

A catalyst solution was prepared under nitrogen using a charge of 7.5 mgof rhodium (0.075 mmol, as rhodium 2-ethylhexanoate); ligand “B”(O,O-di-2,4-α,α-dimethylbenzylphenyl)fluorophosphite), 0.80 g, (1.125mmol); 20 ml of normal butyraldehyde, and 190 ml ofbis-2-ethylhexylphthalate solvent (DOP). The mixture was stirred undernitrogen until a homogeneous solution was obtained (heated, ifnecessary). The mixture was charged to the reactor in a manner describedpreviously and the reactor sealed. The reactor pressure control was setat 17.9 bar (260 psig) and the external oil jacket on the reactor washeated to 85° C. Hydrogen, carbon monoxide, nitrogen, and propylenevapors were fed through the frit at the base of the reactor and thereactor was allowed to build pressure. The hydrogen and carbon monoxide(H2/CO ratio was set to be 1:1) were fed to the reactor at a rate of 6.8liters/min, and the nitrogen feed was set at 1.0 liter/min. Thepropylene was metered as a liquid and fed at a rate of 1.89 liters/min(212 grams/hour). The temperature of the external oil was modified tomaintain an internal reactor temperature of 85° C. The unit was operatedfor 5 hours and hourly samples taken. The hourly samples were analyzedas described above using a standard GC method. The last three sampleswere used to determine the N/I ratio and catalyst activity. The catalystactivity of for the last three hours averaged 13.2 kilogramsbutyraldehyde/gram of rhodium-hour. The product N/I ratio was 1.40.

Comparative Examples 5 and 6 Ligand B

Hydroformylation experiments were carried out in the same manner asComparative Example 4, except utilizing different amounts of Ligand “B”.The reaction conditions and the results of this work are presented inTable 1.

Examples 7-10 Ligand A

Hydroformylation experiments were carried out in the same manner asComparative Example 4, except utilizing various amounts of Ligand “A”.The reaction conditions and the results of this work are presented inTable 1.

TABLE 1 Effects of Ligand to Rhodium Molar Ratio on Activity andSelectivity Example Temp H2/CO Ligand to Rh N/I Catalyst Nos. Ligand (°C.) ratio Molar ratio Ratio Activity* C-1 C 115 1:1 14:1 1.4 15.7 C-2 C115 1:1 30:1 3.1 6.6 C-3 C 115 1:1 50:1 3.8 3.3 C-4 B 85 1:1 15:1 1.4013.2 C-5 B 85 1:1 30:1 1.85 7.2 C-6 B 85 1:1 60:1 2.59 5.0  7 A 85 1:115:1 1.61 3.0  8 A 85 1:1 30:1 1.89 3.23  9 A 85 1:1 60:1 2.50 5.49 10 A85 1:1 90:1 2.72 6.67 11 D 95 1:1  5:1 1.41 3.72 12 D 95 1:1 15:1 1.949.98 13 D 95 1:1 30:1 2.72 15.46 *Activity was determined as kilogramsof butyraldehydes produced per gram of rhodium per hour. All exampleswere done using 0.075 mmol of Rh.

Comparative Examples 1 through 3 illustrate that the hydroformylationreaction activity, under the same reaction temperature and pressure,steadily decreased from 15.7 to 3.3.

Comparative Examples 4, 5, and 6 illustrate again the typical,conventional behavior of phosphorus ligands. Under the same reactiontemperature and pressure, hydroformylation activity steadily decreasedfrom 13.2 to 5.0

Examples 7 through 10 illustrate the desirable nature of Ligand “A”. Thedifference between Ligand “A” and “B” is that “A” has a cyclic ringstructure (methylene group connecting two aromatic rings). Example 7showed an activity of 3.0 for a 15:1 Ligand/Rh ratio. As the ratio ofLigand/Rh increased to 90:1 under the same reaction temperature andpressure, the activity increased to 6.67. The trend of changes inhydroformylation activity in Examples 7 through 10 is completelyopposite to the trend showed in Comparative Examples 1 through 3 orComparative Examples 4 through 6. Examples 11 through 13 illustrate thedesirable nature of Ligand “D”. Example 11 through 13 show that as theligand to rhodium ratio is increased from 15:1 to 30:1, the catalystactivity increases from 3.72 to 15.46 while the N/I ratio shows acorresponding increase from 1.41 to 2.72.

The invention has been described in detail with particular reference topreferred embodiments and illustrative examples thereof, but it will beunderstood that variations and modifications can be effected within thespirit and scope of the invention.

1. A fluorophosphite compound having the structure of formula (I):

wherein Ar₁ and Ar₂ are each independently selected from aryl groupswhich are substituted or unsubstituted, and which contain 4 to 30 carbonatoms; R1 to R6 are each independently selected from H and alkylcycloalkyl and aryl groups which are substituted or unsubstituted, andwhich contain 1 to 40 carbon atoms; and X is (i) a chemical bonddirectly between ring carbon atoms of each aromatic group, except whenR1 to R4 are each methyl, (ii) a heteroatom selected from O, Si, and N,or (iii) a group having the formula

wherein R13 and R14 are each independently selected from hydrogen andalkyl or aryl having 1 to 10 carbon atoms.
 2. The compound according toclaim 1, wherein Ar₁ and Ar₂ are each independently selected from arylgroups having the structure of formulas (II)-(IV):

wherein R7 and R8 are independently selected from alkyl, alkoxy,halogen, cycloalkoxy, formyl, alkanoyl, cycloalkyl, aryl, aryloxy,aroyl, carboxyl, carboxylate salts, alkoxy-carbonyl, alkanoyloxy, cyano,sulfonic acid, and sulfonate salts; m is an integer from 0 to 5; and nis an integer from 0 to
 7. 3. The compound according to claim 2, whereinR7 and R8 are independently selected from alkyl having 1 to 10 carbonatoms, and m and n are independently 0, 1, or
 2. 4. The compoundaccording to claim 1, having the structure of formula (XI):

Wherein R15 is selected from hydrogen and alkyl or aryl having 1 to 10carbon atoms.
 5. The compound according to claim 1, which has thefollowing structure:


6. The compound according to claim 1, which has the following structure:


7. A catalyst solution comprising: (a) a fluorophosphite compound; (b) aGroup VIII metal or rhenium; and (c) a hydroformylation solvent, whereinsaid fluorophosphite compound has the structure of formula (I):

wherein Ar₁ and Ar₂ are each independently selected from aryl groupswhich are substituted or unsubstituted, and which contain 4 to 30 carbonatoms; R1 to R6 are each independently selected from H and alkylcycloalkyl and aryl groups which are substituted or unsubstituted, andwhich contain 1 to 40 carbon atoms; and X is (i) a chemical bonddirectly between ring carbon atoms of each aromatic group, (ii) aheteroatom, or (iii) a group having the formula

wherein R13 and R14 are each independently selected from hydrogen andalkyl or aryl having 1 to 10 carbon atoms.
 8. The catalyst solutionaccording to claim 7, wherein Ar₁ and Ar₂ are each independentlyselected from aryl groups having the structure of formulas (II)-(IV):

wherein R7 and R8 are independently selected from alkyl, alkoxy,halogen, cycloalkoxy, formyl, alkanoyl, cycloalkyl, aryl, aryloxy,aroyl, carboxyl, carboxylate salts, alkoxy-carbonyl, alkanoyloxy, cyano,sulfonic acid, and sulfonate salts; m is an integer from 0 to 5; and nis an integer from 0 to
 7. 9. The catalyst solution according to claim8, wherein R7 and R8 are independently selected from alkyl having 1 to10 carbon atoms, and m and n are independently 0, 1, or
 2. 10. Thecatalyst solution according to claim 7, wherein the fluorophosphitecompound has the structure of formula (XI):

Wherein R15 is selected from hydrogen and alkyl or aryl having 1 to 10carbon atoms.
 11. The catalyst solution according to claim 7, whereinthe fluorophosphite compound has the following structure:


12. The catalyst solution according to claim 7, wherein thefluorophosphite compound has the following structure:


13. The catalyst solution according to claim 7, wherein the Group VIIImetal is rhodium.
 14. The catalyst solution according to claim 13, whichcomprises from about 20 to 300 mg/l of rhodium, and a ratio of grammoles of fluorophosphite to gram atom of rhodium of about 1:1 to 200:1.15. The catalyst solution according to claim 10, wherein the Group VIIImetal is rhodium.
 16. The catalyst solution according to claim 15, whichcomprises from about 20 to 300 mg/l of rhodium, and a ratio of grammoles of fluorophosphite to gram atom of rhodium of about 1:1 to 200:1.17. The catalyst solution according to claim 7, wherein thehydroformylation solvent is selected from alkanes, cycloalkanes,alkenes, cycloalkenes, alcohols, esters, ketones, acetals, ethers,aldehydes, water, and mixtures thereof.
 18. A process for preparingaldehydes, comprising contacting an olefin with hydrogen and carbonmonoxide, under hydroformylation conditions, in the presence of thecatalyst solution according to claim
 7. 19. The process according toclaim 18, wherein Ar₁ and Ar₂ are each independently selected from arylgroups having the structure of formulas (II)-(IV):

wherein R7 and R8 are independently selected from alkyl, alkoxy,halogen, cycloalkoxy, formyl, alkanoyl, cycloalkyl, aryl, aryloxy,aroyl, carboxyl, carboxylate salts, alkoxy-carbonyl, alkanoyloxy, cyano,sulfonic acid, and sulfonate salts; m is an integer from 0 to 5; and nis an integer from 0 to
 7. 20. The process according to claim 19,wherein R7 and R8 are independently selected from alkyl having 1 to 4carbon atoms, and m and n are independently 0, 1, or
 2. 21. The processaccording to claim 18, wherein the fluorophosphite compound has thestructure of formula (XI):

Wherein R15 is selected from hydrogen and alkyl or aryl having 1 to 10carbon atoms.
 22. The process according to claim 18, wherein thefluorophosphite compound has the following structure:


23. The process according to claim 18, wherein the fluorophosphitecompound has the following structure:


24. The process according to claim 18, wherein the Group VIII metal isrhodium.
 25. The process according to claim 24, wherein the catalystsolution comprises from about 20 to 300 mg/l of rhodium, and a ratio ofgram moles of fluorophosphite to gram atom of rhodium of about 1:1 to200:1.
 26. The process according to claim 21, wherein the Group VIIImetal is rhodium.
 27. The process according to claim 26, wherein thecatalyst solution comprises from about 20 to 300 mg/l of rhodium, and aratio of gram moles of fluorophosphite to gram atom of rhodium of about1:1 to 200:1.
 28. The process according to claim 18, wherein thehydroformylation solvent is selected from alkanes, cycloalkanes,alkenes, cycloalkenes, alcohols, esters, ketones, acetals, ethers,aldehydes, water, and mixtures thereof.
 29. The process according toclaim 18, wherein the hydroformylation conditions comprise a temperatureranging from 75 to 125° C. and a pressure from atmospheric to 70 barsabsolute (about 15 to 1,000 psig).
 30. The process according to claim18, wherein the olefin is propylene, and the aldehydes comprise normal-and iso-butyraldehyde.
 31. The process according to claim 21, whereinthe olefin is propylene, and the aldehydes comprise normal- andiso-butyraldehyde.